1. Field of the Invention
This invention relates to a disc cartridge, and more particularly to a disc cartridge which is adapted to rotatably receive a disc medium such as a magnetic disc, a floppy disc, a hard disc, a cleaning disc, an optical disc, a photo-magnetic disc or the like therein.
2. Description of the Prior Art
In general, in a conventional disc cartridge, a floppy disc, a compact disc, a video disc or the like used for a digital-data storing unit, a video unit or the like is rotatably received in a casing for protection against damage and dust to assure its safety. Also, in the conventional disc cartridge, an elastic member is provided on an inner surface of the casing to impel a sheet-like liner in one direction, so that the liner can contact a surface of the disc to clean the surface of the disc and ensure satisfactory contact between the disc and a recording and/or reproducing head (hereinafter referred to as "head") of a disc cartridge operating unit (hereinafter referred to as "cartridge operating unit").
This prior art construction of a disc cartridge will be described with reference to FIGS. 1 to 3.
In the conventional disc cartridge, as shown in FIG. 1, elastic members 100 are mounted at one end thereof on upper and lower inner surfaces of a casing 102 to forcibly contact sheet-like liners 104 arranged in the casing with both upper and lower surfaces of a disc 106 in such a manner as to interpose the disc 106 therebetween.
Alternatively, the conventional disc cartridge may be constructed in such a manner is shown in FIGS. 2 and 3. More particularly, an elastic member 100 is provided on one of the respective upper and lower inner surfaces of a casing 102 and a projecting receiver 108 is provided opposite to the elastic member 100 in a manner to interpose liners 104 and a disc 106 therebetween.
In the prior art disc cartridges constructed as hereinbefore described, the elastic member 100 is made of a sheet composed of material such as metal or polyethylene terephthalate (hereinafter referred to as "PET") and the sheet is bent at a portion thereof mounted on the casing. However, use of a PET sheet for the elastic member causes the bent portion of the elastic member to produce incremental creep deformation with the passage of thus time, resulting in a portion of the elastic member which contacts the disc being gradually positionally lowered. This leads to a decrease the in pressing force with which the elastic member forces the liner against the disc and thus changes the angle .theta. between the elastic member and the disc. Thus, in the conventional disc cartridge, the elastic member fails to effectively maintain the pressing force of the liner against the disc at a constant level for a long period of time, resulting in the liner failing to satisfactory cleaning effect of clean the surface of the disc and satisfactory contact between the disc and a head of a cartridge operating unit consequently cannot be maintained.
In use of a metal sheet for the elastic member, even a slight burr on an edge of the elastic member causes damage to the disc and thus reduces the usable lifetime and the reliability of the disc cartridge.
Accordingly, it would be highly desirable to develop a disc cartridge which is capable of applying a pressing force at a constant level to a cleaning liner for a long period of time and prevent damage of a disc to ensure a long lifetime endurance and high reliability of for the disc cartridge.